In view of the rapid spread of intelligent devices such as computers, semiconductor devices are being rapidly developed. Semiconductor devices are now being required to have high storage-capacity and to operate at high speed. To meet these requirements, technologies for manufacturing semiconductor devices are being developed with an eye toward improving the degree of integration, the reliability, and the response rate of the semiconductor devices.
Generally, semiconductor memory devices are divided into volatile and nonvolatile memory devices. Examples of nonvolatile memory devices include a flash memory device, a McRAM device, etc. The McRAM device includes a first gate electrode functioning as a flash memory and a second gate electrode functioning as a normal gate electrode in a single cell. The McRAM device has recently been in the spotlight due to its advantages (e.g., low power dissipation, low manufacturing cost, and rapid speed of information processing).
Unfortunately, conventional fabrication methods are not able to form an LDD (lightly doped drain) region when fabricating such a McRAM device. Therefore, the McRAM device has not been used to cope with the recent trend that requires semiconductor devices capable of operating at low voltage.